polyline sanity check: Handle border stations and incomplete IRIS routes

					$cache->freeze( $url, $ret );

                   # borders ("(Gr)" as in "Grenze") are only returned by HAFAS.

                   # They are not stations.

					my $iris_stations = join( '|', $train->route );

					my $hafas_stations = join( '|', @station_list );

					my $hafas_stations

					  = join( '|', grep { $_ !~ m{\(Gr\)$} } @station_list );

					if ( $iris_stations ne $hafas_stations ) {

                 # Do not return polyline if it belongs to an entirely different

                 # train. Trains with longer routes (e.g. due to train number

                 # changes, which are handled by HAFAS but left out in IRIS)

                 # are okay though.

					if ( $iris_stations ne $hafas_stations

						and index( $hafas_stations, $iris_stations ) == -1 )

					{

						$self->app->log->warn( 'Ignoring polyline for '

							  . $train->line

							  . ": IRIS route does not agree with HAFAS route: $iris_stations != $hafas_stations"